Electromagnet



Oct; 6

s. c. SMITH ELECTROMAGNET Original Filed Dec. 10. 1920 FIG-8.

lA/VE/VTOH.

Patented Get. 6, 1925.

UNITED STATES PATENT OFFICE.

EDWIN C. SMITH, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO RHODE ISLAND WARP STOP EQUIPMENT COMTANY, OF PAWTUCKET, RHODE ISLAND. A CORPORATION OF MAINE.

ELECTROMAGNET.

Application filed December 10, 1920, Serial No. 429,723. Renewed July 11, 1925.

'1 all whom it may 007166711.

Be it known that I, EDWIN C. SMrrn. a citizen of the United States, residing at Provide ce. in the county of Providence and State of Rhode Island, have invented a. new and useful Electromagnet, of which the following is a specification.

My invention is an improvement in electro-magnets and consists of such a magnet con'iprising in its structure an auxiliary or shunt circuit through the armature which is set up by movement of the armature into contact with a terminal to complete a circuit through the magnet coil so that in case the primary closure is disturbed or accidentally broken, the electro-magnetcontinues to act until the circuit is entirely cut off.

No novelty is claimed for a shunt circuit, controlled by the armature which is admittedly known. The purpose of my invention is to so embody such a shunt magnet, as to make available for the purpose existing elements of the ordinary electro-magnet construction, employing few additional parts, condensing the entire construction within the compass of an ordinary electro-magnet not so equipped and produce a device that can be efiiciently manufactured, not liable to disarrangement, and so free from complications that it can be readily installed and maintained without the exercise of great skill or special knowledge.

The following specification of which the annexed drawings form a part, fully set forth my invention. The said drawings show respectively.

Fig. 1, my improved electro-magnet in sectional elevation, the section being taken on the line a ai of Fig. 2 looking in the direc tion of the arrow b,-

Fig. 2, a side elevation of the electromagnet;

Fig. 3, a. plan View, with the cover and armature removed, looking downward in the direction of the arrow 0; Figs. 1 and 2.

Fig. l, an enlarged view of the top of the magnet coil, showing the attachment of the shunt terminal or contact 4, and the nonmagnetic covering for the end of the core 3;

Fig. 5, a perspective detail of the case;

Fig. 6, a perspective detail of the cover;

Fig. 7, a diagram showing the mode of operation 111 connection with a known electrical warp stop for looms.

Fig. 8, alternative constructions, partly sectional.

Referring to Fig. 1, the principal elements of my invention are the coil 2 with its core 3 and the slmntdevices, which comprise a shunt terminal or contact l and the insulating head or plate 5 on which the terminal l is mounted. The terminal -l is suitably secured, as by rivets 6-6, to the head 5 which may be of fibre 3 and at). The head 5 is rectangular to practically fill the case 7 as shown in Fig. and is secured in place by being forced tightly on the end of the core 3, or on an element connected with the core 3.

The electro-magnet has the usual connective leads 8 and 9 of heavier and more substantially insulated wire than the wire composing the magnet coil. One of these leads 8 merely connects with one end of the coil wire as is usual. The other lead 9 extends beyond its juncture with the other end of the coil wire, through the head of and is attached to the shunt terminal 4 at 9 which is preferably of resilient conducting material such as spring brass. The free end of the shunt terminal l is adjusted away from the head 5 to a height just above the top of the magnet core 3 so that when the armature 10 is drawn down toward the top of the core 3, it hits the extremity of the shunt terminal. The armature 10 being, as will later be explained, connected with one side of the electrical circuit, a shunt circuit is established to maintain the energy of the magnet coil until the shunt circuit is itself broken. See Fig. 7.

The effect of the shunt terminal a is to extend or divert one end of the coil wire into the path of the armature, and in referring to end of coil wire, I do not mean the extremity of that wire essentially, but the portion extending beyond the convolutions of the magnet coil which portion might vary in length according to circumstances. Also in referring to armature, I refer solely to the mass of metal immediately adjacent to the end of the magnet and not to any bearings or arms whereby it is fuicrumed or connected with other devices.

The coil 2, with the shunt attachment as described is enclosed in a case 11, which ma be of cast iron or other suitable material. T prefer, however to use sheet iron or soft steel and have developed a novel construction for such a case.

This construction is more particularly shown in Fig. 5. The case 11 is formed from a sheet blank, made with openings 12-12 to clear the ends of the armature 10, an opening 13 for the arm 14, of the armature openings 15-15 to receive the pin 16, and mortices to receive the tenons 2-1-24- 242-1 as below described.

The edges of the box are spread outward at 171717-17 with flaring dove-tail effect to receive the cover 18 and lock it from being lifted from the case. The cover 18 is formed with side portions that straddle and conform to the sides of the magnet case but flaring outward where they join the top in a substantially internal dove-tail etfect to fit the out spread portions 17l71717 of the case. in those sides 1919 are openings 2020 which, when the cover is in place on the case, register with the holes l5l5 thereof. The armature pin 16 passed through these alining o enings locks the cover from being slid 05 as well as providing a fulcrum for the armature 10. The pin 16 is secured from withdrawal by any suitable means as by heading over, by a cotter pin or by a nut.

In the top of the cover is an adjusting screw 21, by which the movement of the armature 10 is adjusted and limited. A check nut 22 locks the adjustment.

If the magnet core is not thoroughly annealed it retains so much magnetism that it will hold the armature and not release it when the electric current is broken. To prevent this it is customary to insert a small brass pin in the end of the magnet core to prevent actual contact of the armature with the core. This is unsatisfactory because if the pins are too long they reduce the effective movement of the armature which is frequently less than and iftoo short they are not effective because a slight variation in location of the armature pin, or in the size of the pin hole, both of which may be due to ultimate wear, will cause the armature to contact with the core at an angle such that it may touch the core without touching the brass pin.

To serve the same purpose I make a cap 38 of thin brass or other non-magnetic substance. which is t'orced over the end of the core 3, as shown in Figures l-3 and l, and held there by the insulating mounting 5 which is forced over the cap 38. The top of the core is thus completely covered and he armature cannot contact with the core w I: u 4

together by forming the tenons, 24-24-, 2424 over upon the surroundigg the case. The cover when asse' metal of i led bindB blank is folded and the assembly is fastened the case together at the top. The bottom. is formed with provision for mounting the magnet core such as a hole 40 to receive the reduced end 41 of the core 3 which reduced end may be headed over to secure the coil.

The mode of operation of the shunt is shown in Fig. 7 in which A represents the magnet, B the source of electrical energy, a a.

The elecform, with a blade 27 inserted in one ed? be? and insulated from the body by suita means. The drop wire 25, so formed that when it falls it connects the blade 27 and body 26, is normally suspended by thread 28.

One side of the electrical circuit repre-' sented by the line 29, extends from the source of electrical energy B to the blade 1 27 of the electrode D and includes the switch S the opening and closing of which is automaticall controlled by the loom thru means so well nown as to require no description here, and the magnet A with its shunt ar-,.

rangement.

The other side of the circuit re resented by the solid line 30 extends from t e source of electrical energy to the body 26 of the electrode D and has a branch 31 connecting with the magnet armature 10. This branch 31, which is part of the circuit is usually established through the case.of the magnet and the frame of the loom through the;

brackets that support the magnet because in electrical warp stop practice one side of the electrical circuit is grounded in the loom frame. v

\Vhen the thread 28 breaks, the drop wire falls Closing the circuit by connectin the blade 27 and body 26 of the elec e D. The How of current ener 'zes the magnet, pulling the armature 10 own into contact with the shunt terminal 4, thereby estah lishing the shunt circuit. and insuring mag netic energy to hold the armature so long as the latter is kept in touch with the shunt contact. The closer the armature approaches to the core the stronger the mag netic pull and the tighter the armature holds the shunt connection closed. The

iii

function of the magnet of an electrical warp stop is to raise and maintain in position for engagement the dagger 32 or other element of a knock-off device. It sometimes happens that, due to unusual vibration of the loom, thedrop wire and electrode do not make steady continuous contact, due to the dro wire dancing under such vibration. he shunt magnet overcomes this because the drop wire never fails to cause the dagger to rise; although without the shunt, it may not always hold it raised steadily. With the shunt magnet the dagger, once raised, stays raised until the loom is stopped when the current is cut oil from both the primary circuit and the shunt cil" cuit as indicated above by the switch S.

I have described my magnet as being furnished with leads which is usual where the magnet coil is wound with fine wire which would be inadequate to sustain the mechanical treatment of making connections or to resist the injuries to which exposed wires are liable. \Vhere magnet coils are wound from more substantial wire, no separate leads may be required and the shunt contact a may be joined directly to the coil wire as shown in Fig. 8 at 34, where the coil wire is shown looped up through the insulating head 5 for attachment to the contact 4, and the free end is protected by a suitable sheathing or insulation 35.

Likewise it is not essential that the insulating head 5 be secured to the core of the magnet. It can be otherwise secured as shown in Fig. 8 where it is shown mounted on the magnet case 11 which has shelf proections EEG-36 on which the member 5 rests and, locking projections 37-37 which are turned down upon the head 5 to hold it in place on the projections 3636.

By the foregoing construction, I have secured a compact magnet, embodying the shunt system without increasing its outside proportions so the magnet, equipped therewith will occupy no more space than a like magnet without the shunt. The shunt. magnet, as it may be termed, may therefore be readily substituted for like magnets without the shunt attachment.

There is no complication in connecting the shunt magnet for it has only two leads which can be marked by suitable means, as by using different coverings or by using a solid wire for one lead and a stranded wire for the other lead. It is only necessary to assure that the non-shunt lead be connected the source of electrical energy and the shunt lead with the primary closure.

The shunt terminal being interposed between the end of the magnet coil and within the magnet case is protected from dist-urbance and from all liability to short circuits. There are no added levers or bearings to w er and to become deranged.

The case, by its unique construction lends to the compact cture, the sheet metal body insuring les, material without impairing the magnetic e'i'i'cct, besides supplying a construction at once staunch and exceedingly economical to inamifacture. This structure with its locking cover to help support the case is beliercd to possess patentable novelty per se in accordance with the means of the claims presented.

I therefore claim as my invention 1. The combination with a magnet coil and its core, of a case in which the coil and core are n'iounted, an armature, a sliding cover for the case, and a pin to lock he cover to the case on which pin the armature is mounted.

ii. A casing for an electroanagnei. com-- prising a bottom formed with tenons and provision for mounting the magnet coil, a body cut from sheet material with inortices for the said tenons and openings ior the armature and for the arn'iature pin which body is formed to its shape encompassing the bottom and engaging therewith by the mortices and tcnons, and secured thereto by spreading the ends of the tone.

a removable cover and a pin to secure the cover and serve as fulcrum for the magnet armature.

A casing for an electro-maguet formed with openings for an armature and an armature pin and out flaring projecth at the top of the case, a cover formed to engage said out flaring projections also formed with openings for an armature pin and a pin to hold the armature and the cover to the case.

et. In an electro-magnet, the combination with a magnet coil and fulcrumed armature, of a case within which the magnet coil is mounted, which case is formed with mortices, apertures for the armature and pinholes, a case bottom ha *ing provision for mounting the magnet coil and tenons to engage the mortices of the case, a cover with pin holes to register with those of the case, and a pin extending thru the pin holes of the case and cover to lock thetwo and also to serve as fulcrum for the armature.

5. In an electro-magnet, the combination with a magnet coil and fulcrumed armature, a case within which the coil is mounted which case has the outer surface of opposite sides oppositely flared at the top, a cover conformed to the flaring top of the case to hold it thereto, and a pin on which the armature is fulcrumed.

6. In an electro-magnet, the combination with a magnet coil and fulcrumed arn'iature, of a case within which the coil is mounted, a cover fitting the case by sliding engagement and means to lock the cover against sliding, on which means the armature is fulcrumed.

7. In an electro-magnet, the combination 4 nuases with a magnet coil and fulcrumed armature of a case within which the coil is mounted, of a bottom secured to the case by tenons, on which bottom the coil is mounted, a cover conformed to the case top, and a pin to prevent removal of the cover and to mount the armature.

8. In a casing for a magnet, the combination with a bottom having tenons and a substantially central opening and a body cut from sheet metal with mortices for the tenons and a pin-hole at the top, of a cover in sliding engagement with the body and a pin to lock the cover to the body to prevent its sliding.

9. In a casing for a magnet, the combination with a non circular bottom having tenons and a plurality of openings, and a body cut from sheet metal with mortices to fit the tenons and a plurality of openings, of a cover in sliding engagement with the body and having openings registering with certain openings in said body, and means extending thru said registering openings to lock the cover to the body.

10. In a casing for a magnet, the combination with a substantially rectangular bottom formed with a plurality of openings and formed with tenons, of a body formed from sheet metal with mortices to receive the tenons and conformed to the rectangular form of the bottom, and at the top having opposite sides flared outwardly and pierced with holes, of a cover conformed to the outwardly flared top and pierced with holes that register with holes of the body and means extending thru the holes of the body and cover to lock the two together.

11. In a casing for a magnet, the combination with a substantially rectangular bottom 4 formed with a plurality of openings and with tenons, of a body formed from sheet metal with mortices to receive the tenons, the body being conformed to the rectangw lar shape of the bottom to make a rectangncase, and at the top having opposite sides outwardly flared, formed with edge openings and pierced holes, and a cover conformed with the outwardly flared sides. and

pierced with holes that re 'ster with the holes pierced in the outwar flared sides, and means extending thru tlie registering holes of body and cover to lock the two together.

12. In a casing for a magnet, the combination with a substantially rectangular base formed with tenons, of a body conformed to the bottom and having mortices to ining, indented sides and with a third side, of a cover conformed to the two outflaring sides and having perforations that register with those of the bodyffi and means extending thru the re istering perforations to lock the cover to t e body. In testimony whereof I aflix my signature.

EDWIN C. SMITH.

sushi 

